The Animal Physiology Core (APC) employs sophisticated research methodologies to assist Einstein-Mount Sinai Diabetes Research Center (ES-DRC) investigators in the in vivo assessment of glucose and fatty acid metabolism, insulin sensitivity and energy homeostasis in mice and rats. Through collaborative efforts with the other Cores of the ES-DRC, the APC enables investigators to thoroughly characterize the effects of defined pharmacologic, dietary, environmental and genetic alterations on glucose and lipid homeostasis, insulin action, and metabolism. To accomplish these goals, the Animal Physiology Core will: 1) Offer advice and instruction to students, postdoctoral fellows, investigators and technical staff in the design and performance of physiologic approaches and techniques necessary to evaluate the control of glucose homeostasis and insulin action in rodents, 2) Make available to investigators specialized measurements of whole body and tissue-specific glucose metabolism and insulin action in rodent models including insulin, pancreatic and hyperglycemic clamps and spontaneous glucose monitoring, 3) Provide specialized gastrointestinal, neurosurgical and histological models for the study of insulin sensitivity, energy balance, and glucose and fatty acid metabolism, including gastric bypass and adipose and hepatic tissue denervation, imaging and photo-stimulation, 4) Provide analysis of whole body carbohydrate/fatty acid oxidation, energy expenditure, thermogenesis, food intake, and locomotor activity using specialized metabolic (indirect calorimetry) rodent cages, 5) Provide assessments of the effects of diet, exercise, light/dark cycle and environmental temperature on continuous and acute assessments of glucose homeostasis, metabolism, and shivering via electromyography, 6) Make available to investigators specialized measurements of rodent adipose tissue distribution using magnetic resonance spectroscopy, microCT, as well as measurements of glycogen in liver and muscle, intrahepatic lipids and intramyocellular lipids using nuclear magnetic resonance (NMR), 7) Make available to investigators specialized measurements of brain energy and glucose utilization by functional magnetic resonance imaging (fMRI) and microPET scanning, 8) Assist investigators in the interpretation of data and to design further experimental approaches to reveal the molecular and physiological bases of metabolically relevant rodent phenotypes, and 9) Facilitate and integrate the functional assessments provided by the APC with assays provided by other ES-DRC Biomedical Cores. All these services are available to investigators new to diabetes research, as well as to investigators working on diabetes- related projects that can be enriched and extended by the use of the expertise and facilities of this Core.